This invention comprises a liquid tinting shampoo in an aqueous medium providing good lathering properties when used with water, rendering the hair soft and pliable and giving it a long lasting lustrous hair color.
According to the invention, this problem is solved by preparing a shampoo in an aqueous medium, which contains at least one direct hair dye and at least one anionic surfactant, characterized in that the anionic surfactant comprises at least 25% by wt., calculated to the total anionic surfactant composition, of an alkyl amidoether carboxylic acid of formula I ##STR2## wherein R denotes an alkyl group having 8 to 18 carbon atoms, and n is a number between 1 and 10, and/or the water-soluble salts thereof.
R preferably represents an alkyl group from 12 to 14 carbon atoms, and n is a number from 2.5 to 5, particularly 3 to 4.
The anionic surfactant preferably consists of about 30% to 50% by wt. of the alkyl amidoether carboxylic acid according to formula I. Suitable water-soluble salts thereof are particularly ammonium salts and alkali salts such as the sodium or potassium salt; amine salts, too, are suitable.
So-called tinting shampoos have been known and are on the market since a long time. They normally contain anionic surfactants, particularly alkyl sulfates and alkyl ether sulfates, and at least one direct, i.e. semi-permanent, hair dye in an aqueous medium.
While these shampoos present good lathering properties, the intensity of the hair coloration achieved thereby very often is not satisfactory; and also the skin mildness when using these shampoos is not optimal.
Attempts have been made to overcome these disadvantages by using other anionic surfactants, e.g., sulfosuccinates or polyether carboxylic acids and the water-soluble salts thereof, however, this has not led to optimal coloring results either.